Using a model of hypothesis generation to predict eye movements in a visual search task.

We used a model of hypothesis generation (called HyGene; Thomas, Dougherty, Sprenger, & Harbison, 2008) to make predictions regarding the deployment of attention (as assessed via eye movements) afforded by the cued recall of target characteristics before the onset of a search array. On each trial, while being eyetracked, participants were first presented with a memory prompt that was diagnostic regarding the target's color in a subsequently presented search array. We assume that the memory prompts led to the generation of hypotheses (i.e., potential target characteristics) from long-term memory into working memory to guide attentional processes and ocular-motor behavior. However, given that multiple hypotheses might be generated in response to a prompt, it has been unclear how the focal hypothesis (i.e., the hypothesis that exerts the most influence on search) affects search behavior. We tested two possibilities using first fixation data, with the assumption that the first item fixated within a search array was the focal hypothesis. We found that a model assuming that the first item generated into working memory guides overt attentional processes was most consistent with the data at both the aggregate and single-participant levels of analysis.